Is flaw detection required after hot work on industrial pipelines?
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We currently have a 1-inch pipe with a maximum operating pressure of 3 Mpa, and one of the butt-welded check valves in it is damaged and needs to be replaced by installing a new valve. Pipes with a diameter of 1 inch do not fall under the category of pressure pipes. Is it necessary to conduct flaw detection testing after completion? Is there any standard specification? Let’s discuss it together!
Let’s think about it the other way around: what would be the consequences if no flaw detection is carried out after welding? If the welded joint is qualified, then how can you prove that it is qualified? The answer is clear.
Please explain it clearly； What I also need to know is that for the welding, modification, and repair of pressure pipelines, flaw detection is required; this is stipulated in the Regulations on the Supervision of Special Equipment. However, a 1-inch pipeline certainly does not fall under the category of pressure pipelines. Is flaw detection and radiography necessary after the modification? Definitely, a pressure test is required. Can any expert provide some materials?
What is a medium? This is an industrial pipeline, but it does not belong to pressure pipelines. This does not mean that flaw detection can be skipped. It may not be governed by the supervision regulations, but it could be subject to pipeline codes.
Although the pipe diameter is not within the range specified in 1.3a of the General Rules for Pressure Piping, weld inspection is still required for pipes at 3 MPa after welding. Although pressure pipeline regulations classify DN50 as falling under management oversight, smaller pipes still need to be inspected. It’s like when we design containers: although they don’t meet the standards, we still design them in accordance with those standards. There are various types of radiation used for flaw detection nowadays, such as ultrasound; if radiation with a small diameter isn’t suitable, ultrasound is used instead. If neither of these methods is feasible, then magnetic particle testing and dye penetrant testing are alternatives. The flaw detection step cannot be neglected just because pressure testing is being carried out.
The medium is seal oil, similar to white oil. Could you please tell me which regulation specifies this?
You’re right; of course, the more inspection items there are after the modification, the better the quality control will be. But what I want to know is whether there are any regulations that specify this requirement explicitly If it is a pressure pipeline, flaw detection is definitely required after the modification, and I am aware of that as well.
You can refer to SH3501 or GB50517
There is a lot of confusion these days; non-destructive testing is only carried out on pressure pipes under supervision. In fact, non-destructive testing is a method for checking the quality of weld joints, and it isn’t necessarily related to pressure pipes. It’s just that, in order to ensure the quality of welds on pressure pipes, non-destructive testing is required. Even if pressure testing isn’t possible after welding, it’s still advisable to conduct non-destructive testing
Review the design documents to find the pipe property table, which contains the design requirements.
There’s no need for coercion; you can do it on your own and feel at ease